delphi Firemonkey 图片显示拉伸不变形

Firemonkey 图片显示拉伸不变形
Firemonkey 实现简单的图片拉伸不变形，是利用原始图片的 "固定区" 及 "位伸区" 来达到此目的，因此必需要有此结构的图片才适合。

下面以聊天气泡为例，下图四个角为固定区，就是拉伸时，这四个区是不变的，而拉伸区，会自动依位伸的大小自动位伸：

//------------------------------------------------------------------------------

// Design by 龟山阿卍 -

// http://www.cnblogs.com/onechen/ -

//------------------------------------------------------------------------------

unit FMX.Graphics.Helper;

interface

uses

System.Types,

FMX.Graphics;

type

TCanvasHelper = class helper for TCanvas

// 图片四角张缩

procedure DrawBitmapCapInsets(

const Bitmap1: TBitmap; // 图片

const DesRect: TRectF; // 目的区域

const CapInsetsRect: TRectF; // 四角区域

const Opacity: Single = 1.0; // 透明度

const HighSpeed: Boolean = False); // 高速

end;

implementation

// 图片四角张缩

procedure TCanvasHelper.DrawBitmapCapInsets(

const Bitmap1: TBitmap; // 图片

const DesRect: TRectF; // 目的区域

const CapInsetsRect: TRectF; // 四角区域

const Opacity: Single = 1.0; // 透明度

const HighSpeed: Boolean = False); // 高速

var SrcRect: TRectF;

begin

SrcRect := RectF(0, 0, Bitmap1.Width, Bitmap1.Height);

//-------------------------------------------------------------------------

// 最内圈 (不张缩) -

//-------------------------------------------------------------------------

// 左上

Self.DrawBitmap(Bitmap1,

RectF(SrcRect.Left,

SrcRect.Top,

SrcRect.Left + CapInsetsRect.Left,

SrcRect.Top + CapInsetsRect.Top),

RectF(DesRect.Left,

DesRect.Top,

DesRect.Left + CapInsetsRect.Left,

DesRect.Top + CapInsetsRect.Left),

Opacity, HighSpeed);

// 右上

Self.DrawBitmap(Bitmap1,

RectF(SrcRect.Right - CapInsetsRect.Right,

SrcRect.Top,

SrcRect.Right,

SrcRect.Top + CapInsetsRect.Top),

RectF(DesRect.Right - CapInsetsRect.Right,

DesRect.Top,

DesRect.Right,

DesRect.Top + CapInsetsRect.Top),

Opacity, HighSpeed);

// 左下

Self.DrawBitmap(Bitmap1,

RectF(SrcRect.Left,

SrcRect.Bottom - CapInsetsRect.Bottom,

SrcRect.Left + CapInsetsRect.Left,

SrcRect.Bottom),

RectF(DesRect.Left,

DesRect.Bottom - CapInsetsRect.Bottom,

DesRect.Left + CapInsetsRect.Left,

DesRect.Bottom),

Opacity, HighSpeed);

// 右下

Self.DrawBitmap(Bitmap1,

RectF(SrcRect.Right - CapInsetsRect.Right,

SrcRect.Bottom - CapInsetsRect.Bottom,

SrcRect.Right,

SrcRect.Bottom),

RectF(DesRect.Right - CapInsetsRect.Right,

DesRect.Bottom - CapInsetsRect.Bottom,

DesRect.Right,

DesRect.Bottom),

Opacity, HighSpeed);

// 左

Self.DrawBitmap(Bitmap1,

RectF(SrcRect.Left,

SrcRect.Top + CapInsetsRect.Top,

SrcRect.Left + CapInsetsRect.Left,

SrcRect.Bottom - CapInsetsRect.Bottom),

RectF(DesRect.Left,

DesRect.Top + CapInsetsRect.Top,

DesRect.Left + CapInsetsRect.Left,

DesRect.Bottom - CapInsetsRect.Bottom),

Opacity, HighSpeed);

// 上

Self.DrawBitmap(Bitmap1,

RectF(SrcRect.Left + CapInsetsRect.Left,

SrcRect.Top,

SrcRect.Right - CapInsetsRect.Right,

SrcRect.Top + CapInsetsRect.Top),

RectF(DesRect.Left + CapInsetsRect.Left,

DesRect.Top,

DesRect.Right - CapInsetsRect.Right,

DesRect.Top + CapInsetsRect.Top),

Opacity, HighSpeed);

// 右

Self.DrawBitmap(Bitmap1,

RectF(SrcRect.Right - CapInsetsRect.Right,

SrcRect.Top + CapInsetsRect.Top,

SrcRect.Right,

SrcRect.Bottom - CapInsetsRect.Bottom),

RectF(DesRect.Right - CapInsetsRect.Right,

DesRect.Top + CapInsetsRect.Top,

DesRect.Right,

DesRect.Bottom - CapInsetsRect.Bottom),

Opacity, HighSpeed);

// 下

Self.DrawBitmap(Bitmap1,

RectF(SrcRect.Left + CapInsetsRect.Left,

SrcRect.Bottom - CapInsetsRect.Bottom,

SrcRect.Right - CapInsetsRect.Right,

SrcRect.Bottom),

RectF(DesRect.Left + CapInsetsRect.Left,

DesRect.Bottom - CapInsetsRect.Bottom,

DesRect.Right - CapInsetsRect.Right,

DesRect.Bottom),

Opacity, HighSpeed);

// 中

Self.DrawBitmap(Bitmap1,

RectF(SrcRect.Left + CapInsetsRect.Left,

SrcRect.Top + CapInsetsRect.Top,

SrcRect.Right - CapInsetsRect.Right,

SrcRect.Bottom - CapInsetsRect.Bottom),

RectF(DesRect.Left + CapInsetsRect.Left,

DesRect.Top + CapInsetsRect.Top,

DesRect.Right - CapInsetsRect.Right,

DesRect.Bottom - CapInsetsRect.Bottom),

Opacity, HighSpeed);

end;

end.

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